The invention is based on the priority application EP 05292255.6 which is hereby incorporated by reference.
The invention relates to a method for automatically discovering a bus system in a multipoint transport network, plus a multipoint transport network to be used to execute said method, plus a network node to be used in said multipoint transport network.
A network can be defined as a physical arrangement of network nodes that can be logical connected with each other by links.
In a point-to-point network each node can be logical connected by a link with one or two adjacent nodes depending on if the node is the first or last node in a network or if it is lying in between the first and the lost node. The node or the nodes a node can be logical connected with, is the one or are the two physical proximate nodes, one in each direction. So a point-to-point network can be seen as a physical one-dimensional arrangement of nodes that can be logically connected with one physically adjacent node in each direction. A bus system in a conventional point-to-point network is the sum of the one-dimensional logical connections, i.e. the links between aligned adjacent nodes. In a point-to-point network knowledge of the links between the nodes automatically leads to the knowledge of the bus system.
A method to discover a bus system in such a point-to-point network is known from ITU-T G.7714/Y.1705 (August 2005).
With raising data traffic network architecture changes from point-to-point networks to multipoint transport networks (MTN). A MTN is not a one-dimensional arrangement of nodes but can be seen as a two-dimensional arrangement of a plurality of nodes. In a MTN each node potentially can be logical connected with a plurality of physically adjacent nodes. So a bus system in a MTN is not a simple addition of links between one-dimensionally aligned adjacent nodes because in a MTN a plurality of physical proximate nodes exists, each one potentially connectable with its proximate nodes by a link, wherein not necessarily each potential link leads to or is required for a desired bus system. Opposite to current point-to-point connections MTN busses provide a multipoint to multipoint connectivity, which will enhance the load of the network.
For future transport of user data streams like e.g. Internet protocol (IP) data streams within MTN it is necessary to automatically discover bus systems that can be seen as a catenation of a number of links within said MTN. Up to now it is not possible to automatically discover a bus system in a MTN because it is not possible to know in advance which catenation of links provides the desired logical connection between a first and a last node.
From WO 00/52890 A1 a method is known for automatically generating a topology of a network having nodes in form of synchronous optical network (SONET) switches. Thereby the nodes or switches in the network pass information about itself to other nodes or switches in the network so that every node or switch can maintain a topology of the network. Using this knowledge of the network topology, each node or switch can generate a communication bus or route within the network and automatically allot bandwidth for the bus or route. Further, each switch may generate a new bus or route in response to a line failure.
The technical purpose of the invention is to develop a method that allows automatically discovering a bus system in a multipoint transport network, plus a multipoint transport network to be used to execute said method, plus a network node of said multipoint transport network. Care should be taken that the automatic discovering is not carried out for a huge network but restricted to the bus system.